Refrigeration



June 4, 9 .w. H. KlTTO ET AL REFRIGERATION Filed Dec. 23, 1957 2Sheefs-Sheet 1 Patented June 4, 1940 UNITED STATES REFRIGERATION WilliamH. Kitto and Arnold D. Siedle, Canton, Ohio, assignors to The HooverCompany, North Canton, Ohio, a corporation of Ohio Application December23, 1937, Serial No. 181,281

12 Claims.

This invention relates to refrigerating apparatus and more particularlyto control mechanism for such apparatus. In absorption refrigcratingapparatus as previously constructed the control mechanism has beenlocated in the lower part of the cabinet adjacent the boiler therebynecessitating an elongated flexible connection between the manualcontrol means and the regulating device for the control mechanism. Thisarrangement resulted in a diflicult assembly due to the necessity forleading a flexible control cable from a point adjacent the evaporator tothe boiler without sharp bends. Also the flexible cable encased in acoiled wire housing introduced a large frictional load on the controladjusting mechanism with the result that the manual regulatingknob-usually mounted adjacent the evaporator-was diflicult to operate.

A flexible cable connection between the manual adjusting knob and thethermostatic control mechanism introduced a very troublesome adjustingproblem due to the fact that slight elongation of the cables, slippageon the pulleys,

or slipping of the cable housing would destroy the calibration of thesensitive temperature range adjusting mechanism for the thermostaticbellows.

If the gas valve and thermostatic controlling mechanism of an absorptionrefrigerating system is mounted on or adjacent the boiler it is apt tobe injured by the excessive temperature conditions prevailin at thesepoints. The delicate bellows and springs of the thermal control and theaccurately formed gas valve ports may warp orlose their temper ifsubjected to high temperatures. Also the bellows is filled with a fluidwhich expands and contracts with small temperature changes. If thebellows is positioned in a high temperature zone it will not respondaccurately to temperature changes in the cooling unit; this was furthercomplicated by the fact that the capillary tube connecting the bellowsand the bulb mounted on the evaporator had to be of extreme length andwell insulated. However, even with the greatest care, the calibration ofthe control mechanism may be destroyed by heating, bending or elongationof the capillary tube.

Accordingly, it is an object of this invention to arrange a refrigeratorcontrol mechanism in a position not subjected to temperature extremes,permitting a direct positive mechanical connection between the adjustingknob and the temperature range adjusting mechanism, and permitting ashort capillary connection between the bellows in the control mechanismand the thermostatic control bulb in the food cmpartment.

It is a further object of this invention to provide a control mechanismwhich is simply mount-' ed and is positioned to be serviced with aminimum of difliculty.

It is another object of this invention to mount a control mechanism on arefrigerating appa: ratus in such fashion that the entire systemincluding the control may be tested as a unit and may then be mounted ina cabinet as a unit.

It is a further object of this invention to provide a control mechanismhaving a manual adjusting knob which may be operated witha minimum ofeffort on the part of the operator.

It is a further object of this invention to provide a control mechanismadapted simultaneously to control a gas valve and an electric switchwhich regulate the supply of energy to an absorption refrigeratingsystem.

It is a further object of this invention to combine a novel defrostingmechanism with a novel refrigerating control mechanism. 25

Other objects of the invention reside in various arrangements andconstruction of parts which will be apparent as the description proceedswhen taken in connection with the accompanying drawings, in which:

Figure 1 is a partial sectional view of a refrigerating apparatusembodying my invention.

Figure 2 is a horizontal sectional view taken along the line 2-2 ofFigure 1 and looking in the direction of the arrows.

Figure 3 is a partial sectional view on an enlarged scale of my controlmechanism.

Referring now to the drawings and first to Figures 1 and 2 thereof, itwill be seen that I have disclosed a continuous three-fluid absorp- 40tion refrigerating system of the type utilizing a gas burner to generaterefrigerant and a motordriven fan to circulate an inert gas. Therefrigerating system comprises a boiler B, an analyzer A, a rectifier R,a condenser C, an evaporator E, a gas heat exchanger H, an absorber D,and a circulating fan F driven by a motor M. These elements are suitablyconnected in circuit to form a complete refrigerating system.

Heat is applied to the boiler B from a suitable gas burner G ofconventional design and provided with suitable safety-cut-off means. Theboiler B contains a solution of refrigerant in an absorbent, preferablyammoniain Water, which liberates ammonia vapor when subjected to heat.

upwardly through the analyzer A in counterflow to strong absorptionliquid supplied in a manner to be described hereinafter. The refrigerantvapor exits from the analyzer A through a conduit II which is connected.to the condenser C and includes arectifier R. Entrained water vapor iscondensed in the rectifier R and is returned to the analyzer A. Thecondenser C is preferably a tubular finned air-cooled type. Therefrigerant vapor is liquefied in the condenser C and is dis-- chargedthrough a conduit i2 into a finned box cooling conduit l3 forming theupper part of the evaporator E. The liquid refrigerant flows downwardlythrough the evaporator by gravity counter to a stream of an inertpressure equalizing medium, such as hydrogen or nitrogen, which issupplied from the gas heat exchanger H through a conduit l4. A suitabledrain for the evaporator is indicated at l4.

The liquid refrigerant vaporizes into the pressure equalizing medium inthe evaporator to produce refrigeration and the resulting mixture ofrefrigerant vapor and pressure equalizing medium exits from theevaporator through the box cooling conduit l3 and the conduit l5 intothe gas heat exchanger H.

The rich mixture is conveyed from the gas heat exchanger H through aconduit It to the lower end of the absorber D which is preferably of thefinned tubular air cooled type. The vapor-gas mixture passes upwardlythrough the absorber D in counterflow to weak absorption liquid flowingdownwardly by gravity whereby the refrigerant vapor is absorbed in theliquid and the pressure equalizing medium exits from the absorber Dthrough the conduit ll into the suction inlet of the circulating fan Ewhich is driven by a motor M, preferably of the hermetically sealedtype. The gas is discharged under pressure through the conduit l8 intothe gas heat exchanger. The weak gas returns to the evaporator E fromthe gas heat exchanger H through the conduit l4 previously described.

Weak liquor formed in the boiler B as a result of generation ofrefrigerant vapor exits therefrom through the conduit 9, liquid heatexchanger 20, and conduit 2| which communicates with the upper end ofthe absorber D at the point at which the conduit l'l connects with theabsorber D. The strong liquor formed in the absorber D exits from thelower end thereof through a conduit 22, the liquid heat exchanger 20 anda conduit 23 which discharges into the analyzer A. A conduit 24 connectsthe gas discharge conduit l8 with the weak liquor conduit 2| at a pointbelow the liquid level in the boiler-analyzer system whereby the weakliquor is elevated into the upper end of the absorber'by gas-liftaction.

The refrigerating apparatus just described is housed within a suitableinsulated cabinet 38 which is provided with a suitable door 3|. Theevaporator E is positioned in the top central portion of a foodcompartment 32. The refrigerating apparatus with the exception of theevaporator E and the gas heat exchanger H is housed within a space 33extending along the bottom of the cabinet 80 beneath the compartment 32and vertically along the rear thereof.

The vertical portion of the space 33 forms an air-cooling flue forvarious heat rejecting portions of the system. Cooling air enters thespace 33 through suitable openings in the bottom of the cabinet 30 andalso if desired through suitable louvers in the-rear panel 34 of thecabi- Ammonia vapor generated in the boiler B passes net. The coolingair flows upwardly over the aircooled absorber D, the rectifier R, andthe condenser C and exits through suitable openings formed in the top ofthe cabinet 30.

The entire refrigerating apparatus is mounted upon a suitable framework,not shown, and is designed to be inserted as a unit into the cabinet 30after which the rear plate 34 is mounted on the apparatus. A suitablewindow 40 is formed in the rear wall of the cabinet 30 and is designedto be closed by an insulating block 4| which encloses the upper part ofthe gas heat exchanger and the connections to the evaporator and iscarried by the refrigerating apparatus. The insulating block 4| and theinsulated rear wall of the cabinet 30 are formed with a verticallyextending channel 41 which receives the gas heat exchanger H. The openface of the channel 41 is closed by an insulating block 42 which isshaped to embrace the gas heat exchanger and.

to seal the channel.

The control mechanism 50 for the gas burner G and the motor M is rigidlyattached to the block 4| in any suitable manner. The control mechanismis adjusted by means of a manually actuated knob 5| rotatably mounted inany suitable manner in a control panel 52 which is attached to thecasing of the evaporator E and extends thereabove completely con'cealingthe box-cooling evaporator section IS. A control shaft 53 extendsrearwardly from the knob 5| above the finned conduit l3, through theinsulating block 4|, and carries on the outer end thereof a beveled gear54 which meshes with a beveled gear 54' rotatably mounted on the controlmechanism 50.

The control mechanism carries thereon a valve 55 which controls thesupply of gas to the burner G. Gas is led into-the valve 55 from aconduit 48 and is conducted from the valve to the burner G by a conduit49.

Products of combustion from the burner G pass through the boiler B andare conducted therefrom by a conduit into a distributing flue 46. Theflue '46 is flared upwardly from its junction with the conduit 45 andterminates in an elongated discharge mouth adjacent the top portion ofthe cabinet 30. Flue 4c is positioned laterally of the control mechanismto prevent hot products from impinging on the control mechanism and thegas valve.

Referring now to Figure 3, it will be seen that our control mechanismcomprises the casing 50 which rigidly carries on one end thereof the gasvalve which is of a conventional on and oiP type and is provided withthe usual pilot by-pass, not shown. The gas valve 55 is which extendsinto the housing 50 and is suitably guided therein for reciprocatorymotion.

A small coil spring 44 positioned within the housing 50 urges the valve55 to the closed position.

A suitable bellows 51 is slidably mounted in a guide ring 58 which isrigidly mounted in the housing 50 in any suitable manner The bellows 51is provided with a hollow extension 59 which is slidably mounted in abushing 60 threaded into the wall of the casing 50. '-A stifl spring BIis interposed between the bushing 60 and a plate 62 which abuts the endof the bellows 51 and the guide ring 58. The hollow conduit 59communicates through a capillary tube 63 with a bulb element 54 which ismounted on any suitable the housing 50. A suitable collar 66' preventsthe shaft 68 from shifting laterally with respect to the housing 50. Theend of the shaft 68 within the housing 50 is threaded and receives anadjusting nut 69 which is provided with an extension engaging a guiderib I6 formed integrally with the housing 50 to prevent rotation of thenut 69 with the shaft 68. A suitable spring II is interposed between thenut 69 and the actuating arm 66 whereby rotation of the shaft 66 adjuststhe resistance against which the bellows 51 must expand.

The free end of the actuating arm 66 is provided with a conical memberI2 which bears in a depression in a spring retaining cup I3 receivingone end of a snap spring I4. The opposite end of the spring 14 isreceived within aspringretaining cup I5 which has a depressed portionreceiving aconical element I6 carried by a follower arm The follower armI1 is carried by a U-shaped supporting bracket I8, only half of which isshown, pivotally mounted at I9 to fixed support 80. The support 86 alsocarries an adjustable limit stop 86' for the arm 66. It will be seenthat the snap spring I4 is positioned between the arms of the U-shapedbracket I8. The arm 11 is positioned to engage the valve actuating shaft56 at one extreme limit of its movement and to engage one element 8| ofa make and break switch 82 in the other extreme limit of its movement.

The snap mechanism is shown in position to open the valve 55 and toallow the switch 82 to close. In the opposite position of the snapmechanism the spring 44 closes the valve and the follower arm 11 engagesthe element 6| to open the Switch 82.

The switch 82 is connected to a line wire 63 and to a wire 84 which isconnected to the circulating motor M, v

The actuating arm 66 is provided with a latch member 85 which is adaptedto engage a latchkeeper member 86 formed on the end of a defrostinglock-out arm 81 which is pivotally mounted in housing 50 at. 88. A smalltorsion spring 89 urges the look-out arm 81 in a counterclockwisedirection as viewed in Figure 3. Counter-clockwise rotation of the arm81 is prevented by engagement with the plate 62 previously described.The end of the arm 81 engaging the plate 62 is formed with a cam surface9| which will cause clockwise rotation. of the arm 81 when the plate 62is shifted to the leftas viewed in Figure 3.

In operation, the bellows 51 expands and contracts in response totemperature changes in the evaporator E and cycles the switch 82 and gasvalve 55 in a manner to maintain the evaporator within predetermined"temperature limits.

The temperature limits in the evaporator are determined by thecompression of the spring H which is determined by the setting of theknob 5| through the agency of the gears 54 and 54' and the adjustingshaft 53.

Defrostlng is accomplished by turning the knob 5| to the defrostingposition, suitably marked on the panel 52, and then returning the knobto any normal control point, also suitably marked on the panel 52.Movement of the knob 5| to the defrosting position advances the nut 69to such an extent that the spring II will rock the arm 66 in acounter-clockwise direction, as viewed in Figure 3, a distancesufficient to cause the latch member 85 to engage behind thelatch-keeper 86. Under these conditions the bellows 51 is locked againstmovement in a direction to swing the arm 66 in a clockwise direction, asviewed in Figure 3, to open the valve 55 and to close the switch 82, andthe evaporator temperature rapidly increases to a value high enough tomelt frost therefrom.

As the evaporator warms up the bellows 5'! expands to the left, asviewed in Figure 3, and compresses the stiff spring 6|. The plate 62shifts to the left with the slidably mounted end of the bellows andreleases the engagement between the members 85 and 86 by coaction withthe cam surface 9 I when the evaporator has defrosted whereupon thebellows is released and the machine returns to normal operation.

The valve is positioned to be swept by the warm air flowing upwardly inthe space between the panel 36 and the rear wall of the storagecompartment due to the heat rejected by the absorber, condenser, andrectifier. The boiler flue system also induces a warm air flow upwardlythrough the cooling flue. However, the valve is not subjected to hotproducts of combustion as these are discharged laterally of and abovethe casing 56. The warm air stream prevents condensation of water vaporin the gas valve but is not sufficiently hot to injure the valve andcontrol mechanism or to impair the calibration of the control mechanism.

- The control mechanism is adjusted from the control knob by a directand positive connection whereby there is no possibility of loss ofadjustment for the control mechanism by reason of slipping or elongatingcables. Also the operator need only supply sufflcient force to the knob5| to advance or retract the nut 69 and he need not overcome thefrictional resistance inherent in a long encased cable which follows anirregular path.

While we have illustrated and described only a single embodiment of ourinvention, it is to be understood that it is capable of expression inother forms and constructional variations without departing from thespirit of the invention and the scope of the appended claims.

We claim:

1. Refrigerating apparatus comprising a storage compartment, a windowformed in the rear wall of said compartment, a cold-producing mechanismincluding a cooling unit adapted to be inserted into said compartmentthrough said window, a closure member for said window carried by saidcold-producing. mechanism rearwardly of said cooling unit, and controlmechanism for said cold-producing mechanism mounted on said closuremember. 7

2. Absorption refrigerating apparatus comprising a boiler, a condenser,an evaporator, an absorber, means interconnecting said elements to forman absorption refrigerating system including a pressure equalizingmedium circuit between said absorber and said evaporator, power-drivenmeans for circulating a pressure equalizing medium through said pressureequalizing medium circuit, means for applying heat to said boiler,

1 control means for said apparatus mounted at the level of saidevaporator, said control means introl said power-driven circulatingmeans and said means-for applying heat to said boiler.

3. Absorption refrigerating apparatus comprising a cooling compartment,a cooling duct extending vertically in the rear of said compartment, amechanism chamber beneath said compartment, a boiler in said chamber, anabsorber in said chamber and beneath said cooling duct, a condenser insaid duct, a cooling unitin said compartment, means connecting saidboiler, absorber, condenser, and cooling unit in circuit to form arefrigerating system, means for applying heat to said boiler, means forconveying products of combustion from said boiler to an area. adjacentthe top of said cooling duct, and control means mounted in said duct atthe level of the cooling unit and positioned remotely from saidcombustion products discharge area.

4. Absorption refrigerating apparatus of the type involving a boiler anda cooling unit within a storage compartment said apparatus includingmeans to heat said boiler, control means for said boiler heating meanspositioned at the level of said cooling unit, and means shielding saidcontrol means from temperature conditions prevailing at said boiler andsaid cooling unit.

5. Refrigerating apparatus comprising an insulated storage compartment,an evaporator.

mounted in said compartment, a finned boxcooling evaporator conduitmounted on the top wall of said evaporator, an upstanding front panelon'said evaporator arranged to hide said finned box-coiling conduit,control mechanism for said apparatus mounted on the rear wall of saidcabinet at the level of said box-cooling conduit, an adjusting elementfor said control mechanism mounted on said panel, and a directmechanical connection extending above said conduit between saidadjusting element and said control mechanism.

6. Absorption refrigerating apparatus comprising an' insulated cabinet,a mechanism compartment associated with said cabinet, an evaporatormounted within said cabinet, means in said compartment for supplyingrefrigerant to said evaporator including a boiler, an absorber and acondenser, means for heating said boiler, control means for said boilerheating means mounted in said compartment-in position to be swept bywarm air flowing therethrough from said absorber, and means shieldingsaid control means from high temperature conditions existing in thevicinity of said boiler.

7. Absorption refrigerating apparatus comprising an insulated cabinet, amechanism compartment associated with said cabinet, an evaporatormounted within said cabinet, means in said compartment for supplyingrefrigerant to said evaporator including a boiler, an absorber and acondenser, means for heating said boiler, control means for said boilerheating means mounted in said compartment in position to be tween saidcontrol means and said adjusting means.

8. Absorption refrigerating apparatus of the type including a boiler, acombustible fuel burner for heating the boiler and an insulated cabinethousing an evaporator comprising in combination aremovable insulatedpanel in said cabinet adjacent said evaporator, means. for controllingthe supply of fuel to said boiler carried by said panel, means withinsaid cabinet for adjusting said control means, means for shielding saidcontrol means from hot products of combustion discharged by said boilerheater, and means for flowing a warm air current over said controlmeans.

9. Refrigerating apparatus comprising a cabinet, a cooling unit in saidcabinet, control mechanism for said cooling unit mounted on the rearwall of said cabinet at the level of said cooling unit and offsettherefrom, adjusting means for said control mechanism mounted adjacentsaid cooling unit, a drive shaft actuated by said adjusting means, andgearing connecting said drive shaft and said control mechanism.

10. Refrigerating apparatus comprising a cabinet, a cooling unit in saidcabinet, control mechanism for said cooling unit mounted on the rearwall of said cabinet, said control means including an adjusting shaftextending generally parallel to the plane of the rear wall of saidcabinet, adjusting means for said control mechanism mounted adjacentsaid evaporator, an adjusting shaft connected to said adjusting meansand angular motion transmitting mechanism connecting said shafts.

11. Absorption refrigerating apparatus comprising an insulated cabinet,a mechanism compartment associated with said cabinet andincluding aportion extending along the rear wall thereof. an evaporating unitmounted in said cabinet, means for supplying refrigerant to saidevaporating unit including a boiler and an aircooled heat rejecting-unitmounted in said compartment, said heat rejecting unit being arranged todischarge warmed air upwardly along the rear wall of said cabinet,control mechanism for said apparatus mounted in said compartment inposition to be swept by the warm air discharged from said heat rejectingunit.

12. Absorption refrigerating apparatus comprising an insulated cabinet,a mechanism compartment associated with said cabinet and including aportion extending along the rear wall thereof, an evaporating unitmounted in said cabinet, means for supplying refrigerant to saidevaporating unit including a boiler and an aircooled heat rejecting unitmounted in said compartment, said heat rejecting unit being arranged todischarge warmed air upwardly along the rear wall of said cabinet, a gasburner for heating said boiler. a gas valve for controlling said burnermounted in said compartment! above said heat rejecting element, means insaid compartment for operating said gas valve in response to the thermalcondition of said evaporating unit, and means for conducting wasteproducts of combustion from said boiler to waste in a path

